Ggg

    You need to determine if this is actually a robot issue or not, but things I would check are:

    1. Payload is set correctly.

    2. Is the arm at full stretch when cutting, try adjusting so that arm is more constrained.

    3. How many positions are along each side - try a simple corner to corner cut (2 positions).

    4. Laser focal point and settings correctly set.

    Acceleration/deceleration 50%

    Cutting speed 10mm/s - if increased more than 20mm/s problem comes. In 10mm/s cycle time not achieved and also slight weaving problem is there.

    CP switch is ON

    Block teaching is used for programming

    TCP setup done by 4 point method and physically checked no problem

    Transform data is used

    Robot mounted on ceiling and setup also done.

    You still haven't answered about how many points you are cutting between.

    The more points and accel and decel at 50% should be 100%.

    Have you tried point A to point B and what is the result.

    Block programming does not use transformations !!!!!

    So which is it, can we see anything data wise - full file save - perhaps?

    Alexandru raises a good point regarding absolute speed, is this being used?

    With this being a handling robot it will also be optimized to for that application, whereas a sealing robot or arc weld robot would probably be best suited for laser cutting straight out of the box.

    I suggest you read some of the Kawasaki manuals, you're likely to discover something about an XYZ zone in there as well as other factors like block programs, transformations, speed, accuracy, acceleration, deceleration and absolute speeds.

    Applications are not documented, therefore some good understanding of Kawasaki fundamentals is required in order to optimize incorrectly specified robots being used in different applications other than intended.

    Suggestions made here are no guarantees of resolutions, as they are just 'darts being thrown at a dartboard'.

    You may need to consider contacting Kawasaki for specific motion options that may require enabling and adjusting to suit your application needs.

    You may not ever resolve this. Reasons:

    • robots are repeatable, not accurate
    • path accuracy is a tubular tolerance zone around a mathematically perfect path definition and is dynamic based on arm configuration (varies all over the work volume)
    • a robot arm ain't a rigid CNC machine tool
    • servo parameters for individual motors may need tweaking to smooth out those bumps...not recommended
    • some arms are meant for carrying heavy loads point-to-point, not to follow a path

    Servo-tweaking:

    Years ago I was engaged in a project to resolve an out of tolerance condition on a Staubli robot path doing high-precision cutting. The application was analyzed. It showed that the path segment containing the tolerance deviation occurred when the J2 and J3 links went through an inflection point. The arm extended, paused, and then retracted. J2 & J3 opened, paused, then closed. Poof: consistent path tolerance deviation at the inflection point.

    How resolved: some really clever French servo programmer engineers "super-tuned" the servo parameters and sent to us a new servo parameter setting. Problem was corrected. But I hate solutions like that: implementing a "special" in the field and leaving it for the next poor b@st@ard to find.

    Wrong arm use:

    I was tasked with a dispensing job using a refurb BigYella spot welding beast. Dispensing path tolerance is very forgiving. Except this big arm had to move its J5 & J6 in wild gyrations as the dispensing gun traversed around a sharp corner. Angular accelerations were high for J5 & J6. Result: squiggly dispensing lines that could not be programmed out. Cause: big J5 & J6 gears made for carrying heavy payloads, not doing finesse work.

    Quote from arun_AR

    So , as per you quality cannot be achieved ?

    That's not what he is saying.

    Out of the box industrial robots are not designed for the accuracies required for machining etc, they are more of a manipulator than an accurate tool device.

    He is stating that the industrial robot has characteristics that some times the expected outcome is not as simple, straight forward as you expect by using standard application and programming.

    Therefore, sometimes you may require to do carry out some tweaking in order to obtain your required results and this tweaking may require some in depth knowledge of the product in order to succeed.

    However, don't let it put you off, an acquaintance of mine has successfully integrated a D controller using a ZX300 with a plasma cutter/cutting spindle and is producing cut out templates to an acceptable quality.

    So keep going with it and see if you can obtain the required results you need............:top:

    This is where expert tweaking may be required.

    First you need to ascertain 'What' is causing the issue.

    Making sure the fundamentals are as accurate as possible:

    Zeroing, Tool, Weight and location relationship to arm posture.

    It maybe that moving ALL locations so that the arm is using a difference posture may improve things.

    This is the most difficult part as just throwing values at it all over the place is not the way to approach issues like this as you will not find ANY documentation which will suddenly provide a magic wand.

    Very difficult to advise over a public forum without seeing code and some videos perhaps?

  • arun_AR January 27, 2022 at 9:10 AM

    Changed the title of the thread from “Issue in Laser cutting application” to “Ggg”.

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